2 * Copyright 2008 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing.qrcode;
19 import com.google.zxing.BarcodeFormat;
20 import com.google.zxing.EncodeHintType;
21 import com.google.zxing.Writer;
22 import com.google.zxing.WriterException;
23 import com.google.zxing.common.BitMatrix;
24 import com.google.zxing.qrcode.encoder.ByteMatrix;
25 import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
26 import com.google.zxing.qrcode.encoder.Encoder;
27 import com.google.zxing.qrcode.encoder.QRCode;
29 import java.util.Hashtable;
32 * This object renders a QR Code as a BitMatrix 2D array of greyscale values.
34 * @author dswitkin@google.com (Daniel Switkin)
36 public final class QRCodeWriter implements Writer {
38 private static final int QUIET_ZONE_SIZE = 4;
40 public BitMatrix encode(String contents, BarcodeFormat format, int width, int height)
41 throws WriterException {
43 return encode(contents, format, width, height, null);
46 public BitMatrix encode(String contents, BarcodeFormat format, int width, int height,
47 Hashtable hints) throws WriterException {
49 if (contents == null || contents.length() == 0) {
50 throw new IllegalArgumentException("Found empty contents");
53 if (format != BarcodeFormat.QR_CODE) {
54 throw new IllegalArgumentException("Can only encode QR_CODE, but got " + format);
57 if (width < 0 || height < 0) {
58 throw new IllegalArgumentException("Requested dimensions are too small: " + width + 'x' +
62 ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;
64 ErrorCorrectionLevel requestedECLevel = (ErrorCorrectionLevel) hints.get(EncodeHintType.ERROR_CORRECTION);
65 if (requestedECLevel != null) {
66 errorCorrectionLevel = requestedECLevel;
70 QRCode code = new QRCode();
71 Encoder.encode(contents, errorCorrectionLevel, hints, code);
72 return renderResult(code, width, height);
75 // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
76 // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
77 private static BitMatrix renderResult(QRCode code, int width, int height) {
78 ByteMatrix input = code.getMatrix();
79 int inputWidth = input.getWidth();
80 int inputHeight = input.getHeight();
81 int qrWidth = inputWidth + (QUIET_ZONE_SIZE << 1);
82 int qrHeight = inputHeight + (QUIET_ZONE_SIZE << 1);
83 int outputWidth = Math.max(width, qrWidth);
84 int outputHeight = Math.max(height, qrHeight);
86 int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
87 // Padding includes both the quiet zone and the extra white pixels to accommodate the requested
88 // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
89 // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
90 // handle all the padding from 100x100 (the actual QR) up to 200x160.
91 int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
92 int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
94 BitMatrix output = new BitMatrix(outputWidth, outputHeight);
96 for (int inputY = 0, outputY = topPadding; inputY < inputHeight; inputY++, outputY += multiple) {
97 // Write the contents of this row of the barcode
98 for (int inputX = 0, outputX = leftPadding; inputX < inputWidth; inputX++, outputX += multiple) {
99 if (input.get(inputX, inputY) == 1) {
100 output.setRegion(outputX, outputY, multiple, multiple);